Evaluating Expression
Warm Up OBJECTIVE: SWBAT evaluate algebraic expressions. Language Objective: SWBAT describe the steps to evaluating expressions. A magic store is selling exploding pens for $3 each plus $1 for tax. Kyle thinks you can figure out the cost of 10 pens with the below. numerical expression Quick Discussion: Algebraic Expression? 3p+1 Do you agree or disagree? Explain. Click to reveal next part
Launch- Shopping with Marvin Marvin the Math Magician has a problem for you. He wants to buy some magic wands and some magician hats. The wands cost $8 each and $5 for each hat. How much will Marvin have to pay for 12 wands and 7 hats?
Launch- Shopping with Marvin How did you get your answer? The wands cost $8 each and $5 for each hat. How much will Marvin have to pay for 12 wands and 7 hats? How can we write a to show our answer of 131? numerical expression Click to reveal next part
Explore 1- Evaluating with Marvin How much will Marvin have to pay for 6 wands and 3 hats? Write an numerical expression to find the answer. Remember: the wands cost $8 each and $5 for each hat. Click to reveal next part
12 12 7 7 6 6 3 3 8w+5h Explore 1- Evaluating with Marvin The wands cost $8 each and $5 for each hat. Numerical Expression 12 12 7 7 12 wands 7 hats 6 6 3 3 6 wands 3 hats What changed in the two examples? Sometimes it helps to represent a problem as an algebraic expression. 8w+5h w= # of wands h= # of hats Click to reveal next part
h 2 w 10 Explore 1- Evaluating with Marvin How much will Marvin have to pay for 10 wands and 2 hats? w = 10 h = 2 Algebraic Expression This is called substitution!! w 2 h 10 We just evaluated the expression. Click to reveal next part
7 h w 9 9 7 Explore 1- Evaluating with Marvin Find the cost of buying 9 wands and 7 hats. 9 Steps: 1. Copy the expression. w= 7 h= w 9 7 h 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. Click to reveal next part
Flashback… Objective: evaluate algebraic expressions. Explore 2- Formulas Flashback… Objective: evaluate algebraic expressions. We can use the process of evaluating to solve problems in the real world. For example: engineers, architects and builders use geometric formulas every day. Circumference Surface Area Cylinder Volume Rectangular Prism Click to reveal next part
Explore 2- Formulas Volume is the amount of space a shape takes up. The expression for calculating the volume of the rectangular prism is below. 9ft 4ft 5ft or Find the volume 9 4 5 Steps: 1. Copy the expression. 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. Click to reveal next part
Explore 2- Formulas Surface Area is the total of the area of all sides. The expression for calculating the surface area of a rectangular prism is below. 9ft 4ft 5ft Find the volume. Steps: 1. Copy the expression. 2. Substitute the value in for the variable. 3. Evaluate using the order of operations. 9 4 5 9 4 5 Click to reveal next part
Practice- Class work Can’t Wait To Evaluate! a=____ b=____ Directions: Each group receives a set of Evaluation Cards along with two different colored number cubes. Before starting, the team decides which color cube stands for which variable. (Example: the red cube replaces a, the green cube replaces b.) One person in the group rolls the number cubes. Students use the numbers to evaluate the expression. a=____ b=____
Summary Can’t Wait To Evaluate! a=____ b=____ Click each problem for demonstration a=____ b=____
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Exit Slip Kiara was asked to evaluate the expression . Her answer was 14. Did she substitute 11, 13, or 15? How do you know? Answer : 13 27 – 13 14